Production and Behaviour of Aluminium Matrix Double Composite Structures

Abstract:

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In this study Nextel 440 type alumina fibre reinforced aluminium matrix composite wires
were investigated. Composite wires produced using the continuous process are suitable to simplify
the introduction of fibre reinforcements into aluminium castings as well as the production of double
composite, sandwich and preferentially reinforced structures. This paper focuses on the porosity of
composite wires because minimizing porosity is the primary condition of good mechanical
properties. Composite wires were produced with different infiltration pressure (0.83 MPa, 1.03
MPa, 1.24 MPa, 1.52 MPa, and 1.65 MPa) to determine the correlation between infiltration pressure
and the porosity of wires. 10 grinded cross-sectional samples were made from each type of
composite wires. Based on the micrographs of these samples the volume fraction of aluminium was
determined by image analysis, which also yielded information on the porosity of wires. The results
show that there is direct (linear) correlation between the infiltration pressure and the decrease in
porosity. These findings, however, are valid only for the investigated range of pressure. The
measured values were in good agreement with the theoretical model used for comparison.